U.S. patent number 6,678,962 [Application Number 09/716,140] was granted by the patent office on 2004-01-20 for device and method for assessing the geometry of a heart valve.
This patent grant is currently assigned to Cardiomend LLC. Invention is credited to James G. Hanlon, Jack W. Love.
United States Patent |
6,678,962 |
Love , et al. |
January 20, 2004 |
Device and method for assessing the geometry of a heart valve
Abstract
A sizer for assessing the geometry of a heart valve annulus. The
sizer preferably includes a circular sizing portion for measuring
the diameter of the valve annulus. The sizing portion has radial
spokes. The spokes are used to compare the symmetry of the
commissures to the expected symmetry of a normal heart valve. The
sizer preferably has one or more legs attached to the sizing
portion for comparing the contour of the line of valve leaflet
attachment to the expected contour of a normal heart valve having a
diameter substantially equivalent to the measured diameter of the
valve annulus.
Inventors: |
Love; Jack W. (Santa Barbara,
CA), Hanlon; James G. (Camarillo, CA) |
Assignee: |
Cardiomend LLC (Santa Barbara,
CA)
|
Family
ID: |
46203960 |
Appl.
No.: |
09/716,140 |
Filed: |
November 17, 2000 |
Current U.S.
Class: |
33/512; 33/542;
33/555.1 |
Current CPC
Class: |
A61B
5/1076 (20130101); A61F 2/2496 (20130101); A61F
2/2427 (20130101); A61F 2250/0097 (20130101) |
Current International
Class: |
A61F
2/24 (20060101); A61B 5/107 (20060101); A61B
005/103 () |
Field of
Search: |
;33/511,512,555.1,501.45,542,543 ;623/2.11 ;600/587 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Swanson, W. Milton; Clark, Richard E., Dimentions and Geometric
Relationships of the Human Aortic Value as a Function of Pressure,
Circulation Research, vol. 55, Dec. 1974. .
Zioupos, P.; Barbanel, J. C.; Fisher, J., Mechanical and optical
anisotropy of bovine pericardium, Medical & Biological
Computing, Jan. 1992. .
Zioupos, P.; Barbanel, J. C.; Fisher, J.; Wheatly, D.J., Changes in
the mechanical properties of bioprosthetic valve leaflets made of
bovine pericardium, as a result of long-term conditioning in vitro
and implantation in vivo, Journal of Materials and Medicine 4
(1993) 531-537. .
Ioupos, P.; Barbanel, J. C.; Fisher, J., Anisotropic elasticity and
strength of glutaraldehyde fixed bovine pericardium for use in
pericardial bioprosthetic valves, Journal of Biomedical Materials
Researchm Vo. 28, 49-57 (1994). .
Zioupos, P.; Barbanel, J. C., Mechanics of native bovine
pericardium, Biomaterials 1994, vol. 15, No. 9. .
Hanlon, James C.; Suggit, Robert W.; Gibbs, Evan; McMeeking, Robert
M.; Love, Jack W., Geometric Optimization of a Tissue Pattern for
Semilunar Valve Reconstruction, J. Heart Valve Dis, vol. 8, No. 6,
Nov. 1999. .
Love, Jack W., Autologous Pericardial Reconstruction of Semilunar
Valves, J Heart Valve Dis, /vol. 7, No. 1, Jan. 1998..
|
Primary Examiner: Fulton; Christopher W.
Assistant Examiner: Guadalupe; Yaritza
Attorney, Agent or Firm: Bryan Cave LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application
No. 60/165,977, filed Nov. 17, 1999.
Claims
We claim:
1. A sizer for a heart valve annulus having a diameter and a
contoured line of valve leaflet attachment defining a leaflet
shape, the sizer comprising: a first substantially circular
diameter sizing portion for measuring the diameter of the valve
annulus; and a second leaflet sizing portion comprising one or more
arched members attached to the diameter sizing portion for
assessing the leaflet shape, the leaflet sizing portion comprising
one or more arched members, each of which substantially conforms to
a predetermined heart valve leaflet height.
2. The sizer of claim 1, wherein each of the arched members
substantially conforms to the expected shape of a leaflet of a
normal heart valve.
3. The sizer of claim 1, wherein each of the arched members has a
proximal end attached to the diameter sizing portion and an arced
distal end having an apex, wherein the length of said arched member
from the proximal end to the apex of the distal end corresponds to
said predetermined leaflet height.
4. The sizer of claim 3, wherein the predetermined leaflet height
approximates the expected height of a leaflet of a normal heart
valve having a diameter substantially equivalent to the diameter of
the diameter sizing portion.
5. The sizer of claim 1, wherein the one or more arched members is
three arched members.
6. The sizer of claim 1, wherein the diameter sizing portion
further comprises a socket for attaching a handle to the sizer.
7. A sizer for a heart valve annulus having a diameter, a contoured
line of valve leaflet attachment defining a leaflet height, and a
plurality of commissures, the sizer comprising: a first circular
diameter sizing portion for measuring the diameter of the valve
annulus; and a second leaflet sizing portion comprising one or more
arched members attached to the diameter sizing portion for
measuring the leaflet height wherein each arched member has a
proximal end attached to the diameter sizing portion and an arced
distal end having an apex, and the length of each arched member
from the proximal end to the apex of the distal end is
substantially equal to a predetermined leaflet height.
8. The sizer of claim 7, wherein each of the one or more arched
members substantially conforms to the expected shape of a leaflet
of a normal heart valve.
9. The sizer of claim 7, wherein the predetermined leaflet height
approximates the expected height of a leaflet of a normal heart
valve having a diameter substantially equivalent to the diameter of
the diameter sizing portion.
10. The sizer of claim 7, wherein the diameter sizing portion has a
perimeter, the diameter sizing portion further comprising three
radial spokes connected to the perimeter of the circular sizing
portion such that the width of each spoke at the perimeter
designates an arc width that corresponds to a predetermined
acceptable variation from normal symmetry.
11. A sizer for a heart valve annulus having a contoured line of
valve leaflet attachment defining a shape of three valve leaflets,
three commissures, and a diameter, the sizer comprising: a first
circular diameter sizing portion for measuring the diameter of the
valve annulus, the diameter sizing portion comprising a plurality
of radial spokes for comparing the symmetry of the commissures to
the expected symmetry of a normal heart valve; and a second leaflet
sizing portion comprising three arched members attached to the
diameter sizing portion for assessing the leaflet shape, each
arched member comprising: a proximal end attached to the diameter
sizing portion; and an arced distal end having an apex, wherein the
length of the arched member from the proximal end to the apex of
the distal end approximates the expected leaflet height of a normal
heart valve having a diameter substantially equivalent to the
diameter of the diameter sizing portion.
Description
FIELD OF THE INVENTION
This invention relates to measuring instruments and methods and is
particularly directed to instruments and methods used to measure
the size and dimensions of heart valves in the surgical operating
room at the time of heart valve reconstruction or replacement.
BACKGROUND OF THE INVENTION
When a surgeon must replace one or more of a patient's heart valves
because of disease or defect of the native valve(s), the surgeon
must identify the diameter of the patient's annulus in order to
select the correct size replacement heart valve. The measurement of
heart valve diameter in the operating room is typically done with
some type of plug gauge. Gradated sizes of plug gauges, typically
in 2 millimeter increments are used to find the best fit for any
given valve annulus. The advent of homograft valves and, more
recently, methods for reconstructing heart valves, makes it
desirable to determine more than simply the best fit diameter. For
operations involving the use of homograft valves, stentless
heterograft valves, and any one of several methods of aortic or
pulmonic heart valve reconstruction being used, it is also
desirable to measure the height of the leaflets and the symmetry,
or lack thereof, of the valve commissures. To meet these
requirements, an instrument and methods have been developed that
can be used in the operating room to assess valve geometry more
completely than has been possible in the past.
SUMMARY OF THE INVENTION
The present invention is comprised of methods and instruments that
can be used to measure the diameter of the valve annulus at the
commissural level, to compare the height and lines of attachment of
the individual leaflets with reference to a normalized geometry,
and to determine the symmetry of the valve commissures. One
preferred embodiment of the present invention comprises a circular
piece with three equally spaced radial spokes that converge in the
center to a socket to which a handle can be attached. Curved legs
that correspond to the geometry of the normal native valve leaflet
anatomy, as described in published medical articles, are attached
to the circular piece.
In a typical operation to replace or to reconstruct an aortic or
pulmonic valve, the diseased native valve is removed down to the
annulus of the valve. After this has been done, the valve is sized.
With the present invention, sizers of graded dimensions are used
until the best-fit diameter at the commissural level is determined.
With that sizer inserted in the aortic or pulmonic root, the height
of each leaflet from its base to the apex of its commissures can be
compared with the expected dimensions for that valve, based on
published dimensions. The symmetry of the valve can be judged by
aligning any given radial spokes of the circular piece with one
commissure, and then noting the spacing of the remaining two
commissures. The radial spokes each have a width that corresponds
to an arc of the circle that encompasses the normal expected
variation from perfect symmetry. Deviations from expected normal
leaflet height or symmetry can be readily appreciated and used to
increase the precision of the planned surgical procedure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an oblique view from the side of the sizer of one
preferred embodiment of the present invention.
FIG. 2 is an oblique view from the top of the sizer of FIG. 1.
The drawings are provided for illustrative purposes only and should
not be used to unduly limit the scope of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 and FIG. 2 represent two views of a sizer for assessing the
geometry of a heart valve annulus by measuring annulus size,
leaflet height, and leaflet symmetry of semilunar heart valves and
is one preferred embodiment of the present invention. Obviously,
modifications of the present invention can be made to measure
annulus size and leaflet dimensions of tricuspid and mitral valves.
The instrument is preferably molded, cast or machined as a single
unit, preferably from a biocompatible thermoplastic material that
can be readily sterilized and discarded after single use. The
material preferably has sufficient rigidity to maintain its shape
during the sizing procedure, but also a degree of malleability to
make it easy to insert into and withdraw from the valve root
without damaging the tissue. All edges that contact tissue are
round and smooth to avoid damage to the tissue.
In FIG. 1, the sizing portion 1 is used to measure the diameter of
the valve orifice at the commissural level. The sizing portion 1 is
preferably circular. One or more legs 2 define the contoured line
of attachment of a normal leaflet. Each leg preferably has an
arched shape substantially conforming to the expected contour of a
normal heart valve having a diameter substantially equivalent to
the diameter of the sizing portion. As used herein the term "normal
heart valve" generally refers to a heart valve having standard
geometry and dimensions. However, the term "normal heart valve" is
intended to broadly encompass any heart valve dimensions used as a
standard of comparison. As used herein the term "diameter
substantially equivalent to the measured diameter" is used broadly
to refer to a diameter that is the same as, corresponding to,
within a range of, or at a set variance from the measured diameter.
Each leg has a proximal end 2a attached to the sizing portion 1 and
a distal end 2b. The distal end 2b preferably has an arced shape
with an apex 2c. Leaflet height is the dimension 5 which represents
the distance from the top of the circular piece 1 to the apex 2c of
leg 2. This corresponds to the predetermined heart valve leaflet
height which is a ratio of the diameter of the circular piece
1.
Symmetry is assessed by aligning one of a plurality of radial
spokes 3 of the sizing portion with a commissure of the native
valve, and then comparing the alignment of the remaining two
commissures with the other two radial spokes of the circular piece.
Each spoke 3 is preferably connected to the perimeter 1a of the
circular sizing portion 1 such that the width of each spoke at the
perimeter 1a corresponds to an arc width on the perimeter 1a that
corresponds to an acceptable small normal variation from perfect
symmetry. The three spokes 3 are united in the center of the
circular piece 1 by a socket 4 to which a handle can be removeably
attached, either by a threaded connection or by some other quick
connect-disconnect device.
In FIG. 2, some of these same components are identified. The
circular portion 1 has the curved legs 2 to mark the leaflet line
of attachment to the annulus. The radial spokes 3 are joined to the
central socket 4.
The sizer with handle attached is placed in the aortic or pulmonic
root so that the circular sizing portion is at the level of the
commissures. Individual leaflet height and the line of leaflet
attachment to the annulus are determined by comparing the curved
legs 2 with the native valve geometry. Commissural symmetry is
assessed by aligning one spoke with any one commissure and then
noting the relationship of the other spokes with the other
commissures. If all three commissures align within the width of the
spokes where they intersect with the perimeter 1a of the circular
portion 1, the native valve is symmetrical within normal the normal
range of variation.
The sizer can be used in any semilunar heart valve operation where
it is desirable to know the root diameter, leaflet height and line
of attachment, and commissural symmetry. Such operations include,
but are not limited to, valve reconstruction with tissue,
autologous, homologous or heterologous, valve replacement with a
homograft or any type of stentless heterograft, and pulmonary valve
autotransplantation to the aortic position.
Changes, modification, variations and other uses of the subject
invention will be and become apparent to those skilled in the art
after considering this specification and the accompanying drawings
which disclose the preferred embodiments thereof. All such changes,
modification and variations and other uses and applications which
do not depart from the spirit and scope of the invention are deemed
to be covered by the invention. Therefore, it should be clearly
understood that the forms of the present invention described above
and shown in the Figures of the accompanying drawings are
illustrative only and are not intended to limit the scope of the
present invention.
* * * * *